Science and technology news

Insects are repelled by N,N-diethyl-m-toluamide, also known as DEET. But exactly which olfactory receptors insects use to sense DEET has eluded scientists for long. Now researchers at the University of California, Riverside have identified these DEET-detecting olfactory receptors that cause the repellency—a major breakthrough in the field of olfaction.

This image shows the chemical structure of the four compounds found to be strong mosquito-repellents. Credit: Ray Lab, UC Riverside.

Further, the team of researchers has identified three safe compounds that mimic DEET and could one day be used to prevent the transmission of deadly vector-borne diseases such as malaria, dengue, West Nile virus, and yellow fever.

Study results appear online Oct. 2 in Nature.

“Until now, no one had a clue about which olfactory receptor insects used to avoid DEET,” said Anandasankar Ray, an associate professor of entomology, who led the research team. “Without the receptors, it is impossible to apply modern technology to design new repellents to improve upon DEET.”

The method Ray’s team used to identify the receptors examined in an unbiased fashion all the sensory neurons in the insect, which was the key to successfully finding them. In their experiments, the researchers used the genetic model systemDrosophila melanogaster (fruit fly) that was genetically engineered in such a way that neurons activated by DEET glowed fluorescent green. The researchers thus found the receptors, called Ir40a receptors, lining the inside of a poorly studied region of the antenna called the sacculus.